The invention relates generally to photovoltaic devices. More particularly, the invention relates to surface passivated photovoltaic devices having improved conversion efficiency and light confining properties.
Photovoltaic devices, such as solar cells, convert incident electromagnetic radiations into electrical energy. The performance of these devices is measured in terms of their efficiency to convert these incident radiations into electrical energy.
Photovoltaic devices are an environmentally friendly way of producing energy. As such, these devices may provide an increasingly useful option for supplying energy in the future. However, due to the high cost that is often involved in making solar cells, production of such devices may not always provide a viable option to meet all customer demands.
High efficiency solar cells offer an alternative method of cost reduction. In other words, the more power a solar cell can generate, the fewer number of cells are needed to produce the same amount of power. Thus, the overall cost of an efficient and viable photovoltaic device will be reduced. However, various factors, such as recombination of charge carriers, cause a significant loss of energy and only a small amount of incident radiation is effectively converted into electrical energy. Accordingly, cell efficiency may be diminished.
Although, solar cells having a heterojunction structure made by combining crystalline silicon (c—Si) and amorphous silicon (a—Si) have displayed improved efficiencies, there is a need to further enhance the efficiency of these devices while maintaining a low processing cost to make these devices a viable energy source. Accordingly, there exists a need for a photovoltaic device having a relatively high efficiency, which can be processed at low cost.